Optical emitter-detector modules comprise an emitter of radiation like a light-emitting diode and a photosensor like a photodiode, and may be supplied with passive optical elements like apertures or lenses and with an integrated circuit. An opaque element can be applied to reduce optical cross-talk between the emitter and the photosensor.
WO 2013/091829 A1 discloses an opto-electronic module with at least one emission member and at least one detection member mounted on a substrate, which may be a printed circuit board, an optics member comprising at least one passive optical component, and a spacer member arranged between the substrate and the optics member. A portion of the spacer member may be arranged between the emission member and the detection member and thus separate the module into compartments. The emission member and the detection member can each be provided with a lense. The module can be produced by preparing a wafer stack comprising a multitude of the components of the module and separating the wafer stack into a multitude of separate modules each comprising a portion of a substrate wafer, at least one emission member, at least one detection member and a portion of a spacer wafer.
U.S. Pat. No. 8,507,936 B2 discloses an image sensing device comprising a substrate, a photo sensor and an IC stacking layer. An intermediate layer, a micro lens and a micro prism are arranged on top of the IC stacking layer.